Rapid Dating of Recent Aquatic Sediments Using Pu Activities and 240Pu/239Pu As Determined by Quadrupole Inductively Coupled Plasma Mass Spectrometry
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- 作者：Michael E. Ketterer ; Bridgette R. Watson ; Gerald Matisoff ; and Christopher G. Wilson
- 刊名：Environmental Science & Technology
- 出版年：2002
- 出版时间：March 15, 2002
- 年：2002
- 卷：36
- 期：6
- 页码：1307 - 1311
- 全文大小：62K
- 年卷期：v.36,no.6(March 15, 2002)
- ISSN：1520-5851
文摘
Quadrupole inductively coupled plasma mass spectrometryhas been used to rapidly establish the chronology ofrecent aquatic sediments via measurements of the activitiesof 239Pu, 240Pu, and the atom ratio 240Pu/239Pu. Followingaddition of 0.007 Bq of a 242Pu spike isotope, Pu is leachedfrom 3-20 g aliquots of dry-ashed sediments with HNO3.A selective anion exchanger is used to preconcentrate Puinto ~2 mL aliquots, which are directly analyzed using apneumatic nebulizer and double-pass spraychamber operatingat 60 
L/min solution uptake rate. The ICPMS datacollection is performed for 10 min per sample. The Uconcentrations were 0.01-0.05 g/L in the analyzed solutions,and the interference of 238U1H+ upon 239Pu+ was negligible.The method has been applied to determining Pu activities,inventory, and 240Pu/239Pu in a complete sediment core fromOld Woman Creek (Huron, OH). The Pu activity profiles,obtained in ~6 h of instrumental measurement time, are inagreement with a 
spectrometric 137Cs profile. Peak239+240Pu and 137Cs activities in the core were 1.60 ± 0.02and 47.8 ± 0.8 Bq/kg, respectively; inventories were108 ± 2 Bq/m2 239+240Pu and 2710 ± 40 Bq/m2 137Cs. Detectionlimits, based upon the analysis of 20 g samples, were0.004 Bq/kg 239Pu, 0.012 Bq/kg 240Pu, and 0.012 Bq/kg 239+240Pu.240Pu/239Pu atom ratios of 0.16-0.19 were obtained for allcore intervals containing detectable Pu, which indicates thatglobal fallout is the source of these radionuclides.
L/min solution uptake rate. The ICPMS datacollection is performed for 10 min per sample. The Uconcentrations were 0.01-0.05 g/L in the analyzed solutions,and the interference of 238U1H+ upon 239Pu+ was negligible.The method has been applied to determining Pu activities,inventory, and 240Pu/239Pu in a complete sediment core fromOld Woman Creek (Huron, OH). The Pu activity profiles,obtained in ~6 h of instrumental measurement time, are inagreement with a spectrometric 137Cs profile. Peak239+240Pu and 137Cs activities in the core were 1.60 ± 0.02and 47.8 ± 0.8 Bq/kg, respectively; inventories were108 ± 2 Bq/m2 239+240Pu and 2710 ± 40 Bq/m2 137Cs. Detectionlimits, based upon the analysis of 20 g samples, were0.004 Bq/kg 239Pu, 0.012 Bq/kg 240Pu, and 0.012 Bq/kg 239+240Pu.240Pu/239Pu atom ratios of 0.16-0.19 were obtained for allcore intervals containing detectable Pu, which indicates thatglobal fallout is the source of these radionuclides.